The overall plan is to determine the feasibility and validity of using short-term cell culture assays in conjunction with clinical evaluation to assess the sensitizing potential resulting from the interaction between common metals and their organic sequestering compounds present in the environment. The specific aims are: 1. To evaluate the usefulness and reliability of the cytoskeletal perturbation assay using both rodent cells and human skin fibroblasts in culture for deveelping an in vitro short-term test system to systematically screen various environmental agents, particularly common metals in combination with their organic sequestering compounds, for their potential to induce skin hypersensitivity reactions in humans. 2. To evaluate whether the combined metal/organic sequester antigens, administered at the same patch site, exacerbate the hypersensitivity responses in patients known to have positive patch tests to either sensitizing agent alone. 3. To evaluate using in vitro lymphocyte activation assay the enhancing effect of the metal/sequester combination over cultures containing individual antigens. 4. To evaluate in patients with double sensitivity whether the clinical avoidance of the combined antigens results in substantial improvement or clearing of chronic diseases not responsive to conventional therapy and/or avoidance of one or the other antigen. 5. To systematically compile data on chemical structure/metal valence interrelationships followed by computer analyses using graphic software with matching capability in order to determine which chemical groups in three dimensions are combined with which metal valences to produce the strongest or weakest responses in both in vivo (patch tests) and in vitro assays (cytoskeletal perturbation and lymphocyte activation). This information on structure/sensitizer relationship will be useful in predicting as yet untested environmental agents that might be potential sensitizers.